The invention concerns an air filter with a filter element in a filter housing, comprising an adsorber element for adsorption of hydrocarbons.
U.S. Pat. No. 7,641,720 B2 discloses an air filter for the intake manifold of an internal combustion engine wherein the air filter comprises a filter element in a filter housing and the filter element is flowed through by the supplied combustion air. Downstream of the filter element an adsorber element is integrated in the flow passage of the air filter with which hydrocarbons, which flow back in the direction of the intake manifold after shut-down of the internal combustion engine, can be adsorbed. After restarting, the hydrocarbons that are adsorbed in the adsorber element are then released again into the air flow and transported in the direction of the cylinders of the internal combustion engine.
The adsorber element is embodied as guide vanes which project into the flow passage and are provided with an adsorption layer. In this context, care must be taken that, on the one hand, the flow resistance caused by the guide vanes is not increased in an impermissible way and, on the other hand, a sufficient adsorption capacity is ensured.